Stability of probiotic yogurt added with glucose oxidase in plastic materials with different permeability oxygen rates during the refrigerated storage

The stability of probiotic yogurts added with glucose oxidase and packaged in different plastic packaging systems that present different oxygen permeability transfer rates (0.09, 0.2, 0.39 and 0.75 mL O-2/day) was evaluated during 28 days of refrigerated storage. Probiotic stirred yogurts were submitted to physicochemical (pH, proteolytic activity, dissolved oxygen) and microbiological analyses (yogurt bacteria, Lactobacillus acidophilus and Bifidobacterium longum) as well as the content of organic acids (lactic and acetic acid) and aroma compound (diacetyl and acetaldehyde) were assessed. Overall, yogurts packaged in plastic containers with lower oxygen permeability rates showed a higher extent of post-acidification, proteolysis and organic acid production. Additionally, these samples also presented a lower content of dissolved oxygen and a lower decrease of the probiotic bacteria count. No influence on the production of aroma compounds was observed. Our results suggest that the use of packaging systems with different oxygen permeability rates coupled with the addition of glucose oxidase presented an interesting technological option to minimize the oxidative stress in probiotic yogurts. (C) 2013 Elsevier Ltd. All rights reserved.